The goal of these studies is to define the sites in DNA which regulate normal erythroid cell development. In this research, the use of a series of mutants in beta globin biosynthesis, the beta thalassemias and related disorders are studied in order to define the defect in DNA structure, and the changes in beta globin mRNA biosynthesis which accompany these disorders. Restriction endonuclease analysis has already defined deletions of all or part of the delta and beta globin structural genes in some rarer forms of thalassemia, delta beta thalassemia and hereditary persistence of fetal hemoglobin (HPFH). However, restriction enzyme analysis of DNA from several patients with beta and beta thalassemia from Mediterranean populations has thus far failed to reveal differences in the restriction endonuclease digestion patterns. This may be due to the relatively small changes in DNA accompanying these disorders, which go undetected by restriction endonuclease analysis. Therefore, studies have begun in which unfractionated human cellular DNA has been used to specifically clone the beta and delta human globin genes. This cloning has utilized charon 4A lambda phage DNA as the vector and E. Coli DP50SupF as host. Clones have already been obtained which contain the complete delta and beta genes from a patient with beta thalassemia, and this DNA is available for comparison with that of cloned DNA from a non-thalassemia patient. These DNAs will be compared directly by extensive restriction endonuclease analysis and direct nucleotide sequencing using Maxam-Gilbert procedure. The analysis of several normal DNAs, and beta and beta thalassemia DNAs, will be required to distinguish the changes in cellular DNA which are important for globin gene expression from those unrelated to regulating beta globin gene expression.